Super power efficiency is the hallmark of the P90 Series of on-line UPS products. Not only does the P90 provide completely isolated, clean, stable power to critical electronic equipment, it does so with very low power consumption rates - a feature important for compliance with industry guidelines for energy use reduction and resource conservation. On-line (a.k.a. double conversion) circuitry provides a continuous charge on the UPS batteries while maintaining a complete barrier against any form of surge or voltage transient, no matter how small or how fast. Wall power is used to charge the batteries which are then the only source for regenerated AC power for the connected equipment (AC > DC > AC). There's no need for a power conditioner with an on-line UPS. Power Factor Efficiency - In addition to buffering against power line problems, the P90's sophisticated design extracts the most from available power line voltage and current. Real AC power equals volts times amps times power factor (W = V x A x PF). So, a 1,000VA power supply with a 0.70 power factor will supply 700 watts of power. That's very typical of most UPS models. But, the P90 is designed with a 0.90 power factor and produces almost 30% more real power in the same situation. That means a lower cost of operation and in many cases allows use of a smaller, less expensive UPS. Click here for in-depth information about power factor => http://en.wikipedia.org/wiki/Power_factor ECO Mode Efficiency - Beyond the higher power factor, the P90 ECO Mode feature allows a power bypass of the double conversion circuitry when line voltage is within an acceptable range. Eliminating the overhead load of the UPS when not needed increases operating efficiency of the UPS to 98%. (Note: ECO Mode operation is selectable during the UPS set up.) The P90-PRO Series features an extended four year warranty plus a professional grade rack rail mounting kit and is available exclusively from Juice Goose. The P90-PRO Series is comprised of four models: 1000VA, 1500VA, 2000VA and 3000VA. Each can be rack, tower or wall mounted.